Method of constructing a field-erected vapor-storage vessel



Jan. 17, 1956 v, L N 2,730,798

METHOD OF CONSTRUCTING A FIELD-ERECTED VAPOR-STORAGE VESSEL Filed April 27 1950 United States Patent '0 Lyle V. Larsen, Chicago, 111., assignor to Chicago Bridge and Iron Company, a corporation of Illinois Application April 27, 1950, Serial No. 158,503

2 Claims. (Cl. 29-475) This invention relates to vapor storage vessels and more particularly to spherical and/or semi-spherical vapor storage vessels and the method of constructing the same.

Liquid and gas pressure vessels usually have shell thicknesses enabling the individual plates comprising the shell to be self-supporting during construction of the vessel. With such vessels very little or no construction framing and support is needed for building up the tank shell. Generally, such vessels having curved sides, are built up of plates oriented with theirgreates't dimension extending in a generally vertical direction on the shell. Thus, in this type of plate layout, it may be said that the axis of plate layout is vertical.

Vessels for the storage of vapors are made of relatively thin steel plates which are flexible and do not have sufficient rigidity to be self-supporting if constructed in a manner similar to that used for the construction of pres sure vessels. The present invention provides a new and useful method of constructing such vapor storage vessels without the necessity of temporary supports for the thin plates comprising the completed shell.

The invention will be described with reference to embodiments of the invention shown in the accompanying drawings, in which:

Fig. 1 is a side elevational view of a completed vaporsphere;

Fig. 2 is an elevational view of the vaporsphere illustrated in Fig. 1 taken at 90 thereto;

Fig. 3 is a plan view of the vaporsphere illustrated in Fig. 2;

Fig. 4 is an elevation of a vaporsphere showing an alternate scheme of plate layout;

Fig. 5 is a broken plan view of the vaporsphere shown in Fig. 4.

Vapor storage vessels, such as the vaporsphere illus trated in Fig. 1, may be used to store vapor forced out of one or more oil storage tanks by thermal expansion or filling, or vapor derived from other sources. Such vaporspheres may be made in capacities generally ranging from 5,000 to 150,000 cubic feet. Vapordomes may be mounted directly on the top of the roof of a storage tank and comprise, generally, a hemisphere. Other vapor tanks having other configurations may be used and constructed in a manner similar to that hereinafter described for the vaporsphere.

In Fig. 1, the shell of a vaporsphere is supported by spaced legs 11 mounted on foundation blocks 12. The legs 11 are suitably braced and support the weight of the shell 10. The vapor storage vessels may be made from the lightest workable material, normally no more than inch steel plate. The only pressure to which the vessel is subjected is that from the vapor itself, which is very small, or that provided by a flexible diaphragm such as illustrated in the co-pending continuation in part application of Wissmiller, Serial No. 146,379, filed February 25, 1950.

Since the plates comprising the shell 10 are very flexible and relatively thin, construction framing has been utilized the spherical vessel.

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in the past to hold the plates in their proper shape until the shell is completed.

In Fig. 2, each individual plate segment 18 is in the general shape of an orange peel lune-like section of the shell. The segments each lie between meridians 19 of the spherical shell, passing through the poles 35 of the horizontal polar axis. Each segment 18 has one curvature extending generally between the poles, but is flat in a transverse direction or in other words, is not dished. Thus as viewed in Fig. 2, the shell is not exactly spherical but approximates a sphere.

In constructing the shell, the legs 11, here shown as tubular vertical columns, are first placed in position on the foundation blocks 12 and an equatorial belt of plates secured to the supporting columns. Two or more supporting columns may be used depending upon the size of In the case of relatively small vessels, two supporting columns may be sufficient; the two supporting columns each being secured to a spherical seg mentally shaped head plate 21 and the equatorial belt then secured to the head plates. The equatorial belt may comprise one or more segments; segments 18a, 11, c and ti along with head plates 21 comprising the belt in Fig. 2.

The plates comprising the segment of the shell are cylindrical segments having longitudinal edges comprising arcs of a circle. Since the plates are very thin and flexible,

they may be shipped flat and bent lengthwise in the field while remaining fiat transversely to conform to the proper segmental shape. When secured in position, the longitudinal edges of the segment follow meridians of the shell passing through the poles of the horizontal polar axis.

After the equatorial belt is properly positioned as above described, other plate segments are successively secured thereto to complete the lower hemisphere of the shell. Each plate segment is supported during construction by the previously secured adjoining plate segment. After the lower hemisphere is completed, plate segments are successively secured upwardly from the equatorial belt to complete the upper hemisphere. In this manner of construction, very little or no temporary support is necessary. The plate segments are each oriented about the horizontal polar axis so that a straight line between the ends of each plate segment along the greatest dimension of the plate is parallel to the horizontal polar axis.

The plate layout illustrated in Figs. 4 and 5 shows a spherical shell built up of courses 24 of plates each comprising a frustum section of a cone. A center equatorial belt course 24a is first secured to the supporting columns 11. The plates being thin and flexible are bent to the segmental shape as they are secured in position. Other frustum plate segments are then successively secured to the equatorial belt segment both downwardly and upwardly therefrom. A spherical segmentally shaped head plate 25 is secured to the upper and lower frustum to complete this spherical shell. The individual frustum segments may be formed in the shop to a spherical segment shape if desired.

Each frustum shape is secured to either the segment immediately above or below it, as the case may be, and is supported during construction by the adjoining segment. By this construction, each segment is supported along its greatest dimension so that the shape of the segment will be retained without the necessity of temporary supports. In this form a straight line between the ends of the greatest dimension of the plate segment is parallel to the horizontal polar axis.

The equatorial belt 24a may comprise a cylindrical section, if desired. The adjoining segments will be frustums and if the vessel is small enough, the head plates 25 may be fiat. The operating pressures to which the vessel is subjected are sufliciently small, that the shape departures stresses.

The foregoing detailed description has been given for clearnessof understanding onlyand' changes, therefore;

- the said two columnsgtorming. thin, flexible, not self-suptinuing in like manner to secure additional lune-like shaped plates to the previously erected plates as well as the head plates to complete the vessel. shell.

2. The method of constructing a field erected vapor storage vessel; having a relatively thin steel-plate shell of generally spherical shape, comprising; erecting vessel supfromltruly spherical, cause negligible increases in plate '4 porting columns at the construction site; forming thin, flexible, not self-supporting flat pre-cut shell plates-into a vessel segment shaped like a frustum of a cone, securing said frustum shaped segment to the columns without the aid of falsework so that the segment forms a generally horizontal belt portion of the vessel; then consecutively securing other frustum shaped vessel segments to the erected segments without the aid of falsework; and securing spherical segmental shaped head" plates to the frustum shaped segments at the top and bottom to complete the vessel shell. V

References Cited in the file, of this patent UNITED STATES PATENTS 1,621,984 Horton Mar. 22, 1927 1,940,785 Boardman Dec. 26, 1933 1,958,421 Daniels May 15, 1-934 2,118,388 Zerbe May 2 4, 1938 2,126,997 Kramer Aug. 16, 1938 2,228,736 Starworth Ian. 14, 1941 2,287,197 Sandberg June 23, 1942. 2,287,198 Sandberg June 23, 1942. 2,427,676 Horton Sept. 23, 1947 2,517,853 Eickmeyer Aug. 8, 1950 2,628,418 Branson Feb. 17, 1953 V FOREIGN PATENTS 398,439 Great Britain Sept. 14, 1933 401,073 any Jan. 1, 1943- France Jan. 10, 1945 

1. THE METHOD OF CONSTRUCTING A FIELD ERECTED VAPOR STORAGE VESSEL HAVING A RELATIVELY THIN STEEL-PLATE SHELL OF GENERALLY SPHERICAL SHAPE, COMPRISING; ERECTING VESSEL SUPPORTING COLUMNS AT THE CONSTRUCTION SITE, A PAIR OF SAID COLUMNS BEING POSITIONED OPPOSITE EACH OTHER ON A HORIZONTAL AXIS OF THE SHELL, SECURING A HEAD PLATE TO EACH OF THE SAID TWO COLUMNS; FORMING THIN, FLEXIBLE, NOT SELF-SUPPORTING FLAT PRE-CUT SHELL PLATES SUBSTANTIALLY INTO A LUNELIKE SHAPE BUT NOT CURVED BETWEEN THE SIDES; SECURING THE SO-FORMED LUNE-LIKE SHAPE PLATES AT THE ENDS TO SAID HEAD PLATES AND AT THE SIDES TO OTHER OF SAID COLUMNS WITHOUT THE AID OF FALSEWORK SO THAT THE PLATES FORM A GENERALLY HORIZONTAL EQUATORIAL BELT PORTION OF THE VESSEL SHELL; FORM- 